An automatic transmission, or transaxle, sits between an engine, typically an internal combustion gasoline engine or diesel engine, and a rotating wheel axle, and transfers power from the engine to the axle of a vehicle. An automatic transmission includes a torque converter that is a fluid coupling that enables the engine to continue to rotate independently of the transmission. When the engine speeds up, more fluid is pumped into the torque converter, causing more torque to be transmitted to the wheel axle. When the engine is rotating slowly, such as when the car is idling at a spotlight, the amount of torque transmitted to the wheel axle is very small. Some torque converters include a lockup mechanism that binds the engine to the transmission when their speeds are nearly equal, to avoid slippage and a resulting loss of efficiency. The automatic transmission automatically changes gear ratios as the vehicle moves in order to provide a range of speed and torque outputs. Typical gear ratios can range from 4-speed, and up to 10-speed. Having a greater number of gears can provide a smoother transition between gears, but can also lead to a more complex transmission system.
An automatic transmission has an associated set of performance standards that it is required to meet. An automatic transmission with a greater number of gears has greater complexity, making achieving performance standards more difficult. Failure or wear of components in sections of the automatic transmission can prevent the system as a whole from achieving the expected level of performance. Tests may be used to determine if the automatic transmission is within the performance standards. In particular, tests may be performed during manufacturing to determine quality of the transmission. Also, tests may be performed for troubleshooting a transmission returned under warranty.
However, it is a difficult and time consuming task to determine what component, or components, may be the reason that the expected performance level of an automatic transmission is unable to be achieved. Test results are complex and require a highly trained person to analyze the results and determine possible components that may be the cause of poor performance. For example, test results can consist of several hundred values for various parameters, for which the values are meaningless without some understanding of the values that parameters are expected to have under specific conditions.
The foregoing “Background” description is for the purpose of generally presenting the context of the disclosure. Work of the inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.